1. Field of the Invention
The present invention relates to a cover unit, and especially to a cover unit used for sealing an opening of a USB socket of a USB flash disk.
2. Description of the Prior Art
A USB flash disk is a mobile storage device, its capacity is much larger than a compact disk (CD) now after fast progression, and is convenient for carrying, it is used very widely.
A USB flash disk is provided with a protruding USB jack, it is provided thereon with an opening being subjected to getting entering of impurity or small materials, the opening with a USB connector must be sealed with a cover provided over the USB jack.
In the prior art, a Utility model application with a publication No. M356200 titled “USB FLASH DISK WITH A NON-TOUCHING SENSING CHIP” in Taiwan discloses a design of the above mentioned cover. Wherein the cover is integrally injection shaped, if it is desired to firmly cover, the internal tolerance of the cover must be made to tightly match the USB connector, this renders the cover to need larger force to overcome the impedance coming from tightness against slipping over and extracting. And more, a conventional tightly matching type cover not only needs larger force for slipping over and extracting, it also has a defect of being unable to tightly cover being due to suffering of the cover from pressing that induce damage or due to damage by friction in a long term using; therefore improvement is needed.